The present invention relates to an apparatus for continuously breaking up into smaller, more manageable fragments, a continuously formed and fed, thermoplastic slab or sheet material. The present invention also relates to a method of using the slab breaking apparatus "in-line" to rapidly and continuously brake down friable thermoplastic slab or sheet material into fragment pieces thereby preventing deposition, accumulation, or jamming of slab or large particulate material in the apparatus housing. The apparatus is particularly useful in thermoplastic processing industries where continuously formed, sheet materials or formulated slabs, arising from the intermediate product of, for example, a melt mixing device or extruder, are continuously broken into smaller more easily processed fragments or pieces.
Machines which employ related pinwheel or rotating rods having radially projecting tines are known in the art, however, these devices have been employed principally for the purpose of particulate separation in continuous processing equipment, for example, separating seeds from cotton, and agricultural produce, and not for the combined purposes of expediting material handling, jam elimination, and particle size reduction, as in the present invention.
A problem frequently encountered in the processing of thermoplastics, particularly melt mixed or extruded materials, which are initially formulated, for example, in melt mixing equipment and in a continuous slab form, is the jamming or accumulation of slab material, that is, non particulate or non flowable solid slab fragment material, during a slab fragmentation step or comminution of the slab monolith into smaller, more easily handled, fragments or pieces. The generation or accumulation of non-particulate material in slab breaker machines can result in, for example, fouling of the machine and can lead to decreased material throughput and processing rates, and changes in particle size distribution properties of the educing particulate stream. Excessive accumulation of non-particulate material may result in equipment failure or require terminating the process stream and operation because of other process complications, arising downstream, due to the particulate material being too large for subsequent size reduction or particulate treatment equipment, for the inherent hazard potential to man and machine, and for the purpose of subsequent removal of accumulated non flowable particulates, and which process termination is costly and counterproductive.
The present invention provides, in embodiments, solutions to the aforementioned problems including large particulate accumulations or material buildup within a slab breaker means and the accompanying negative productivity impacts. The prior art does not, it is believed, recognize, address or solve the aforementioned problems as in the present invention which employs a thermoplastic slab breaking apparatus with improved slab breaking efficiency and efficacy.